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ReasoningonDynamicallyBuiltReasoningSpacewithOntologyModulesFabioPortoEPFL-EcolePolytechniqueFédéraledeLausanneSchoolofComputerandCommunicationSciencesDatabaseLaboratory,1015Lausanne,SwitzerlandFabio.porto@epfl.chAbstract.Severalapplicationsrequirereasoningoverautonomouslydevelopedontologies.Initiallyconceivedtoexplicitthesemanticsofacertaindomain,theseontologiesbecomeapowerfultoolforsupportingbusinessinteractions,onceheterogeneitieshavebeensolvedandinconsistencieseliminated.Unfortunately,astablecoherentlogicalstateishardtomaintaininsuchanenvironment,duetonormalevolutioncarriedoutindependentlyoverindividualontologies.Asaresult,reasoningoverautonomouslydevelopedontologieshastofacewithbothheterogeneityandinconsistency,inordertoassurecorrectanswering.Inthispaperwestudytheproblemarisinginthesesettings.Weproposeanincrementalreasoningapproachbasedonavirtualreasoningspacethatisfilledwithrelevantontologyentitiesasqueryansweringprogress.Weshowhowtoidentifythesetofrelevantentitieswithrespecttoauserqueryusingasettheoryapproachandillustratethesolutionwithausecaseexploringthewebservicediscoveryscenario.1.IntroductionTheuseofontologiestoformallydescribeadomainhasbeenadoptedbyapplicationsinvariousareaslikebioinformatics[1,12,13],business[14,15],transportation[16,17]etc..Suchincreasinginterestonontologiestosupportallkindsofwebrelatedandwebagnosticapplicationsdonot,however,pointtoafutureglobalanduniformontology[18]butrathertoasetofautonomouslyspecifiedones.Inspiteofconsideringthischaracteristicasprecludingtheuseofsuchontologies,manyauthorshaveinvestigatedamoregeneralstrategyforreasoningoverontologiesthataredistributedandautonomouslyspecified[2,7,19,20,21].Reasoningoverdistributedandautonomousdevelopedontologieshastofaceanumberofnewchallenges.First,currentreasoners[23]considerontologyasformingasinglelogicaltheory.Unfortunately,bothdistributionandautonomyadverselycontributetosuchaview.Thereforeinordertousecurrentreasoningsoftwarethesetofautonomousdevelopedontologiesmustbealignedandintegratedintoasingleconsistentontology.Second,asinthecontextofdatabaseintegration[22],andtoallowbuildingasinglelogicaltheory,definitionondifferentontologiesmustbealignedbytheuseofcorrespondenceexpressions.Thirdly,thesetofinvolvedontologiesmaygettoaquitevoluminousamountofdata.Asaresult,anaïvesolutionoftransferringallontologiestoalocationandthenproceedwithlocalreasoningdoesnotscaleup.Finally,autonomouslydefinedontologiesmayassertcontradictorydefinitions,whichsomeauthorsclassifyasconflictsintheintegrationprocess.Conflictsidentificationis,infact,atoolforfixingcorrespondenceassertionsandapplyingontologyalignment.So,reasoningunderthissettingshouldbecapableofidentifyingsuchconflictsandactingappropriately.Inthispaper,weproposeanewstrategyforbuildingasingleontologyoutofautonomouslydevelopedonestoansweranontologyquery.Weconsideranontologytogetherwithasetofcorrespondenceswithotherontologiesformingaontologymodule.Ontologyqueriessubmittedtomodulesareansweredbyreasoningoveradynamicallybuiltreasoningspacecomprisingrelevantontologyentitiescapturedamongautonomousdevelopedontologies.Wegivesomeinitialideasonhowtodynamicallybuildareasoningspaceandpointtofurtherresearchissues.Therestofthispaperisstructuredasfollows.Section2presentstheconceptsofontologyspacesandontologymodules.Next,section3developsthestrategyofbuildingareasoningspacetoanswerreasoningqueriesoveranontologyspace.Section4usesascenarioofwebservicesdiscoverytoillustratetheapproach.Insection5,wecommentonrelevantrelatedworkand,finally,section6givesourconclusionsandpointtosomefuturework.2.OntologySpaceandModulesAutonomouslydevelopedontologiesemergequitenaturallyindifferentbusinessareas.Howeverasbusinessevolves,interactionsamongpartnerspromotetheextensionofeachone’sactivitiestowardsanetworkofinterrelatedprocessanddata.Ifautomationisrequiredtosupportthebusinessprocess,theindependentdevelopedontologiesmayproveusefulinsolvingsemanticmisunderstandingsbyofferingawidersemanticcoverforreasoningtasks.Wenameasetofautonomouslyspecifiedontologiesoverwhichanhypotheticalreasonercouldevaluateanontologyqueryanontologyspace(OS).GivingtwoontologiestakingpartinaOS,wesaythattheyintersectifthereisaknowncorrespondenceassertionassociatingentitiesinbothontologies.Thesetofentitiesspecifiedinaontologytogetherwithasetofcorrespondencesexpressedwithentitiesinotherontologiesdefineanontologymodule(M).Theunderlyingontologyofamoduleisnameditsbaseontology.Anontologyentityinamoduleiseitherdefinedinitsbaseontology,localentity,oraddedtoitbyanequivalencecorrespondencewithanexternalentity,specifiedinadifferentontology.TheconceptofmodulesissimilartocontextinC-OWL[2].Definition1:AmoduleisasetMo=id,D,L,C,Ob,Os,whereidcorrespondstoaUniqueResourceIdentifier(URI)forthemodule,Disthedescriptionofthemodule,eitherexpressedinnaturallanguageorbymeansofanontologylanguage;ListheontologylanguageusedinMo;Cisasetofcorrespondences(definedbelow)associatinglocalentitieswithentitiesdefinedinexternalmodules;ObisthebaseontologyandOsisthesetofexternalontologiestowhichcorr